Water hammer arrester



Feb. 17, 1942.

E. B. H. TOWER, JR

WATER HAMMER ARRESTER Filed Aug. 4, 1940 2 Sheets-Shed 1 a E .F

Feb. .17, 1942. as. H, TOWER, JR WATER HAMMER ARRES'I ER Filed Aug. 4,1940 2 Sheets-$heet 2 TIME m sncou'ns AFTER cLusuRE 0F QUICK ACTINGVALVE 0N TEST PIPE 5 5. w mm ,W u Mm A, EFY. 2 ?v 2 V T ETC .1 PFU U-UmwbV m 5 5 w. wm w mflm GB mm PS1... W 9 CT 4 Mmm PG? 3 5 v v m n o a w aA .L A i 0 m m .m A 1, o dun! a mmmm 5 mmzzmmpfis on. E5 m n mu @335 E$555.8 H3535 mm m Patented Feb. 17,- 19s.!

I WATER HAMMER Annns'rnn Edwin B. H. Tower, Jr., Milwaukee, Wis.Application August 4', isiaser'iai No. 351,412

4 Claims. (01. 138-30) The invention relates to a water hammer arresteror other energy absorbing appliance of the type in which abnormalimpulses or fluctuaor other conduit are suppressed by compression of agas or other compressible fluid medium to prevent water hammer.

When water or other liquid which is in transit under pressure through apipe or other con duit is brought to an abrupt stop by closing a valve,periodic surges in kinetic energy are propagated in the water andoscillatein recurring cycles through the water between the valve and thesource of pressure until the energy is dissipated. 1 v

These periodic surges in energy causeabnormal impulses or fluctuationsin pressure of such order as to produce violent concussion, called waterhammer, which subject the pipe and its joints to enormous stresses andproduce loud bangs-or other objectionable noises.

' tions in pressure of water or other liquid in a pipe When water hammeroccurs, the pipe and its I joint are liable to burst or rupture, andappliances connected" to the pipe are injured or damaged.

In order to suppress the abnormal impulses liable to be or fluctuationsin pressure to a sumclent extent to prevent water hammer, energy must beabsorbed from the water at a sufficient rate to cause a substantialreduction in the rate of -variation of the pressure of the waterthroughout the surges in energy and thereby impose such limitation uponthe impulses or fluctuations in pressure as to prevent water hammer.--'

Appliances have been proposed in which a casing encloses a chamberpartitioned by a plicated bellows into an-expansion compartment 1 toreceive water from a pipe and a compression compartment to confine a gasor other compressible fluid medium, but such appliances lack ability tocompress at a suflicient rate such mass arrester which is small in sizerelative to its of gas as is required; to suppress to a sufficientextent throughout, the surges in energy the im' pulses or fluctuationsin pressure causing water to en-v hammer. I

These appliances further lack ability sure to a suiilcient extent toprevent water ham- I mer.

Another object is to provide a water hammer arrester which will increasethe rate of absorption of energy from the water over the rate 0!"absorption of energy by compression of the compressible; fluid confinedwithin the compression compartment. Another object is to provide a.water hamme arrester in which the bellows will act upon the water uponincrease in the pressure thereof to' effect a substantial increase inthe absorption .of energy therefrom.

Another object is to provide a water hammer arrester in which'thebellows will be guided .by the casing and substantial'energy will beabsorbed by displacement of fluid between the bellowsand the casing.

Another. object is to provide a water hammer arrester which willdissipate to a substantial extent. the energy absorbed in suppressingthe impulses or fluctuations in pressure and thereby diminish'themagnitude of each succeeding impulse or fluctuation in pressure andaccelerate the dissipation oi the entire energy. I

Another object is to provide a water hammer arrester, in which thebellows will require less deflection to cause suflicient energy to beabsorbed to'prohiblt water hammer.

Another object is to provide a water hammer arrester which will endureinnumerable shocks in absorbing energy to suppress the impulses orfluctuations in pressure causing water hammer. Another object is toprovide a water hammer arrester which. will protect a pipe and itsjoints from impulses or fluctuations in pressure that are liable toburst or rupture the pipe and its joints and injure or damage appliancesconnected to the pipe. 7

Another object is to provide a water hammer capacity to absorb anddissipate energy.

Another object is to provide a water hammer arrester which maybearranged in any position inrelation to the pipe to receive water therefrom. 1

' Another object is to provide a water hammer dure the shocks imposedupon the bellows by the Y impulses and fluctuations in pressure ofthewater in the expansion compartment.-

The present invention has for. its object to provide awater hammerarrester which will possess permanent capacity to absorb energy at asuflicient rate throughout'the surges in energy to suppress, theimpulses or fluctuations in pres.-

arrester which is inexpensive to manufacture and install .and which doesnot require attention in service.

Another object isto provide 'a water hammer arrester which is simple inconstruction and durable and emcient in service.

According to the present invention as it is ordinarily embodied inpractkc, the bellows is the casing to guide the bellows upon deflectionthereof and form constricted passages between the bellows and the casingof an order to throttle displacement of fluid between the bellows andthe casing to absorb energy from the pressure fluid upon deflection ofthe bellows by the impulses in pressure.

When the bellows is contracted by the water within the expansioncompartment, the water in the annular pockets between the plaitsisdisplaced through the constricted passages between the plaits and thecasing and thereby the rate of absorption of energy from the water isincreased to diminish the ultimate rise in pressure during the surges inenergy.

The present invention is applicable in particular to a water hammerarrester in which a casing ispartitioned into an expansion compartmentand a compression compartment by a plicated metallic bellow which willdeflect within its elastic limits to compress a suflicient mass ofcompressible fluid or medium to absorb energy at a suflicient rate toprohibit water hammer.

The compressible fluid or medium confined within the compressioncompartment is ordinarily a permanent foam so as to increase the rate ofabsorption of energy in relation to the deflection of the bellows;

Although the invention is described herein as applied to prevent waterhammer caused by impulses or fluctuations in the pressure of water, itis applicable to prevent water hammer caused by impulses or fluctuationsin the pressure ofoil or other liquid, and the term "water hammer" asemployed herein denotes and comprehends water hammer caused by any fluidor liquid.

The water hammer arrester shown in the accompanying drawings exemplifiesthe invention as embodied in practice, and the views in these hammerarrester at the lower part with the bellows contracted by the initialimpulse or fluctuation in pressure.

Fig. 4 is a chart depicting by a curve the impulses or fluctuations inpressure causing water hammer and another curve the impulses orfluctuations in pressure as suppressed by the water hammer arrestershown in the drawings.

The water hammer arrester is provided with a cylindrical casing I havingan integral dome '2 at the top and a removable base 3 at its bottom.

The base has a peripheral flange 4 screwthreaded to thecylinder and acentral inlet 5 surrounded by a collar 6.

The casing'is partitioned by a plicated metallic bellows I into anexpansion compartment 8 to receive water or other liquid through theinlet 5 and a compression compartment 9 to confine a gas or othercompressible fluid and mineral oil or other incompressible fluid. I

The bellows is supported within the casing by a head l0 having anintegral post H passing through a tapered aperture in the dome Zandhaving. a tapered section l2 intermediate its ends to bear in thetapered aperture.

The postisprovided upon its upper end with a nut 14 screw-threadedthereon todraw its ta- 1 provided with plaits fltting close to the wallsof pered section into the tapered aperture and thereby retain the headin a fixed position.

The bellows is composed of annular metallic disks l5 which are united-toeach other at the inner and outer perimetersinalternation by flanges l6formed on the disks'and brazed or otherwise fastened in grooves. H inthe disks.

The bellows is thus provided with plaits forming alternate internal andexternal elongated pockets.

The top disk has its flange brazed or otherwise fastened in a groove'inthe head Ill, and the bottom disk is closed at itscenter by-a cap i9brazed or otherwise fastened thereto.

'The compression compartment contains a gas or other compressible fluidand a mineral oil or other incompressible fluid, and the mineral oiloccupies about one-half /2) the volumetric capacity of the compressioncompartment.

The gas and the mineral oil are intermingled with each other byagitation to form a foam or emulsion throughout the entire compressioncompartment, and such foam is stabilized by a small quantity of tinctureof quillaja or other foam stabilizing agent mixed with the mineral oil.

The mineral oil is introduced into the bellows through an aperture inthe cap on the bottom disk, and then the aperture is sealed by solder.

The bellows is of such size as to provide a compression compartment withsuflicient volumetric capacity to contain the mass of gas and mass ofoil required to enable the water hammer arrester to be efiective inpreventing water hammer under the conditions to which it is subjected inpractice.

The bellows is further made deflectable within the range of its elasticlimits to effect suflicient variation in the volumetric capacity of thecompression compartment to compress the gas to absorb suflicient energyfrom the surges in energy to prevent water hammer.

- The mass of the oil is limited to render its inertia insuflicient toimpede the compression of the gas to any substantial extent ornecessitate employing a bellows of such length that it will be distortedor buckled intermediate its nds upon compression.

The water hammer arrester is shown applied to prevent water hammer in apipe 20 having a valve 2i to stop the flow of water or other liquidthrough the pipe.

The casing is connected to the pipe near the valve to admit water orother liquid from the pipe into the compression compartment.

When the flow of water through the pipe is brought to a sudden stop byclosing the valve, surges in energy are propagated in the water in thepipe and tend to produce abnormal impulses or fluctuations in pressureof the order causing water hammer.

Inasmuch as the magnitude of the impulses or fluctuations in pressuredepends upon the size of the pipe andthe rate of flow of water in thepipe at the instant the valve is closed, the mass of gas in thecompression compartment is proportioned according to these conditions.

That is, the gas has its mass proportioned to absorb uponvariations inits compression by variations in the pressure exerted by the water inthe expansion compartment, suflicient energy from the surges in energyto cause such reduction in the rate of variation in the pressure of thewater in the v expansion compartment throughout the surges in energy asto impose a aavavce "3 sumcientlimitation upon the impulses orfluctuations in pressure to prevent water hammer.

The gas has its compression relative to the variation in the volumetriccapacity of the compression compartment amplified by the oil. to 5effect suflicient compression of the gas upon deflection of the bellowswithin .therange oi-rits elasticlimits to prevent water hammer. But theoil has its mass limited to render its inertia insufliicent to cause anysubstantial difl'erence between the rate of variationin the compressionof the gas in the compression compartment and the rate of variation inthe pressure exerted bythe water in the expansion compartment. v 5

*I'he bellows is provided with plaits forming annular pistons fittingclose to the chamber within the casing to guide the bellows upondeflection thereof and form constricted passages between the plaits andthe walls of an order to throttle displacement of fluid from theexternal pockets between the pistons to absorb energy from the fluidwithin the compression compartment upon deflection of the bellows byimpulses in pressure.

When thebellows is contracted the water is displaced from the pocketsbetween the plaits and through the constricted passages to absorb energyfrom the water and thus reduce the ,amplitude and magnitude of theimpulses or fluc- -tuations in pressure.

The chart. shown in Fig. 4 .depicts by a curve a v the abnormal impulsesor fluctuations in pressure tending to be produced by the surges inenergy propagated upon the sudden stoppageof the 5 flow of water throughthe pipe by closing the I valve under thefollowing conditions:

Pipe three-quarters inch in diameter, one

hundred and fifty (150) feet long from source of pressureto valve.

' Static pressure of waterin pipe with valve closed, about fifty (50)pounds.

Flow pressure of water through pipe with valve open, about five (5)pounds.

Rate of flow of water about ten (10) feet per second.

, Pressure of initial impulse or fluctuation in pressure about sixhundred (600) pounds. Duration of initial impulse or fluctuation inpressure one-fifth (V5) second.

When a water hammer arrester, such as described herein and shown in thedrawings, is provided with a bellows containing about fifteen (15) cubicinches of air and'about fifteen (15) cubic inches of oil, and having itsdimensions about three (3) inches in diameter and about twelve (12)inches in length expanded and about six (6) inches in length contracted,the initial impulse or fluctuation in pressure is reduced by compressionof the air in the compression compartment to about two hundred (200)pounds,

- as indicated by the curve b.

The pressure of the initial impulse or' fluctuation in pressure isfurther reduced, as indicated 'by curve c, upon contraction of 'thebellows by.- the energy absorbed in. displacing the water from thepockets between the plaits inthe bellows and through the constrictedpassages between the, plaits and the casing.

Inasmuch as energy is absorbed from the water 7 by its displacementthrough the constricted passages between the bellows and the casing, thebellows requires less deflection than would otherwise be required tocause suflicient energy I to be absorbed-to prohibit water hammer. 7 5

The invention described and claimed herein may be applied in variousways for different purposes to absorb energy from water or other fluidssubject to impulses or fluctuations in pressure.

The water hammer arrester may be modified V in its proportions accordingto the energy it is required to absorb and the conditions under which itis to operate.

The invention exemplified by the water hammer arrester described hereinand shown in the drawings may assume various embodiments which will bewithin its scope as defined by the claims. I

' i The invention described in the foregoing speciflcation and shown inthe drawings forming a part thereof, is hereby defined and claimed asfollows:

1. An energy absorbing appliance for suppressing water hammer or.similar purposes, comprisingin combination, a casing enclosing acylindrical chamber and having an inlet to admit pressure fluidsubject-to impulses in pressure, a plicated metallic bellows arrangedwithin said casing to partition said chamber into an expansioncompartment to receive said pressure fluid and a sealed compressioncompartment to con.- tain a compressible fluid to absorb energy fromsaid pressure fluid and said bellows having its plaits forming annularpistons fitting close to the walls of said chamber to guide said'bellowsupon deflection thereof and form constricted passages between saidplaits and said walls of an order to throttle displacement of fluid fromthe external pockets, between said pistons to absorb energy from saidpressure fluid, upon deflection of said bellows by said impulses inpressure, and a compressible fluid confined within said sealedcompressioncompartment to absorb energy from said pressure fluid uponits impulses in pressure to limit the amplitude of its fluctuations inpressure.

2. An energy absorbing appliance for suppressing water hammer or similarpurposes, comprising in combination, a casing enclosing a cylindricalchamber and having an inlet to admit pressure fluid subject to impulsesin pressure, a plicated metallic bellows arranged within said casing topartition said chamber into an expansion compartment to receive saidpressure fluid and a sealed compression compartment to contain acompressible fluid to absorb energy from said pressure fluid and saidbellows being composed ofannular disks spaced apart from each other andjoined together at the inner and outer perimeters thereof in alternationby flanges formed thereon and said disks forming annular pistons flttingclose to the walls of said chamber to guide said bellows upon deflectionthereof and form constricted passages between said disks and said wallsof an order to throttle displacement of fluid from the external pocketsbetween said pistons to absorb energy from saidpressure fluid upondeflection of said bellows by said impulses in pressure, and acompressible fluid confined within said sealed compression compartmentto absorb energy from said pressure fluid upon its impulses in pressureto limit the amplitude of its fluctuations in pressure.

8. A water hammer arrester, comprising in combination, a casingenclosing a cylindrical chamber and having an inletto admit watersubject. to impulses in pressure, a plicated metallic bellows arrangedwithin. said casing to partition said chamber into an expansioncompartment between said bellows and said casing to receive said. waterand a sealed compression compartwater upon its impulses in pressure tolimit the .amplitude of its fluctuations in pressure.

'4. A water hammer arrester, comprising in combination, a casingenclosing a cylindrical chamber and having an inlet to admit watersubject to impulses in pressure, a plicated metallic bellows arrangedwithin said casing to partition said chamber into an expansion com- 20partment between said bellows and said casing to receive said water anda sealed compression compartment to contain a compressible fluid toabsorb energy from said water and said bellows being composed of annulardisks spaced apart from each other and joined together at the inner andouter perimeters thereof in alternation by flanges formed thereon andsaid disks forming annular pistons fitting close to the walls of saidchamber to guide said bellows upon deflection thereof and formconstricted passages between said disks and said walls of an order tothrottle displacement of water from the external pockets between saidpistons to absorb energy from said water upon deflection of said bellowsby said impulses in pressure, and a compressible fluid confined withinsaid sealed compression compartment to absorb energy from said waterupon its impulsesin pressure to limit the amplitude of its fluctuationsin pressure.

EDWIN B.- H. TOWER, JR.

Cancellation of Patent Patent No. 2,273,766, February 17, 1942, Edwin B.H. Tower, J12, WATER HAMMER ARRESTOR.

On October 21, 1949, the District Court of the United States for theEastern District of Wisconsin rendered judgment by consent in U. S. v.Edwin B. H. Tower, J12, Civil Action N o. 4268, and ordered adjudged anddecreed that: United States Letters-Patent No. 2,273,766, issuedFebruary 17, 1942, to defendant be and hereby is canceled ab initio. Theabove udgment has been recorded in the assignment records, liber V221,page 555.

[Ofiicial Gazette December 13, 1.949.]

